Random motion suction cleaner

ABSTRACT

A self-propelled device adapted to move along the bottom of swimming pools or other water tanks in a random pattern to clean the surface thereof. The cleaner has low-voltage motors for driving, sensing means to sense contact with walls, and electronic logic means to direct the motion of the cleaner according to certain requirements. The cleaner has a suction inlet, a strainer, and is connected by means of a hose to a relatively high-voltage pump above the water level. The logic means provides for lock-out of spurious signals, pause times, and turning by selected drive wheel reversals. Various modifications and broad applications of certain of the principles are possible.

United States Patent 1 1 Wulc 145] July 1,1975

[ RANDOM MOTION SUCTION CLEANER Stanley S. Wulc, Rydal, Pa

[73] Assignce: Total Enterprises, Inc., Hathoro, Pa. [22] Filed: July18, 1972 [21 Appl. No.: 272,846

Related US. Application Data [62] Division ot'Serv No. 28.453. April [4.1970, Pat. No.

[75] lnventor:

[52] US. Cl 180/65; l80/79 [51] Int. Cl 862d 11/04 [58] Field of SearchISO/6.5, 79 791. 6.28. 180/2, 98; l5/l.7; 56/102; 46/244 R [56]References Cited UNITED STATES PATENTS 2.770.074 11/1956 Jones et al v.46/244 R 3.130.803 4/1964 Wiggins A t 180/65 3,550 7l4 12/1970 BellingerU [BO/79.1

Primary Examiner-Leo Friaglia Assismnr E.\'aminerJohn A. Pekar Attorney.Agent. or FirmPaul Maleson [57] ABSTRACT A self-propelled device adaptedto move along the bottom of swimming pools or other water tanks in arandom pattern to clean the surface thereof. The cleaner has low-voltagemotors for driving, sensing means to sense contact with walls, andelectronic logic means to direct the motion of the cleaner according tocertain requirements. The cleaner has a suction inlet. a strainer. andis connected by means of a hose to a relatively high-voltage pump abovethe water level. The logic means provides for lock-out of spurioussignals, pause times. and turning by selected drive wheel reversals.Various modifications and broad applications of certain of theprinciples are possible.

4 Claims. 9 Drawing Figures SHEET I I I I 25a 21 Fly 4 1. 4/

I a 4" 60L 61 64 610 a T0 PUMP (SUC I'ION) MOTOR CONTROL HALT aacx TURNTIME mas TIME I SWITCH INTERFACE SWITCH 1| SWITCH 2| Hg 50 nuwwmuu SHEETW m a Fig. 3

RANDOM MOTION SUCTION CLEANER This is a division of application Ser. No.28,453, filed Apr. l4, i970 now U.S. Pat. No. 3,676,774.

BACKGROUND OF THE INVENTION 1. Field of the Invention In its basic orexemplary form, this invention relates to a random motion suctioncleaner for swimming pool bottoms. It is required from time to time toclean such pool bottoms to remove debris and certain growths and othermaterials. Suction cleaners attached to hoses and handles are oftenused. Self-propelled devices have been known to perform this function.

While the preferred embodiment of this invention has been specificallydeveloped and designed for use in swimming pools and for submergedservice into other tanks, certain aspects of the drive, control, andlogic of the device are suitable for broader application. Generally,such broader application involves a case in which it is desired to havea self-propelled device moving across a horizontal surface to cover itin a random pattern, and provide it with sensing means and logic andcontrol means whereby the device senses obstructions and turns away fromthem to continue its motion in a random manner, with a high degree ofeffeciency and a minimization of the possibility of the device becomingtrapped by certain configurations of the obstacles.

2. Description of the Prior Art It is known to clean the submergedsurfaces in tanks by suction means. It is known as a broad concept toprovide devices adapted to move along surfaces in a random manner and toturn away from the boundaries of the selected surface. Such devicesinclude lawnmowing machines which sense electrically operated boundrymarkers. In the pool cleaning field, known expedients include suchdisclosures as in US. Pat. Nos. 2,923,954; 3,32l,787; 3,324,492;3,439,368; and Austrailan Pat. No. 9648/27. These citations areexemplary, not exhaustive.

The present invention has a number of advantages over prior expedients,particularly considering the earlier known random devices for cleaningthe bottoms of swimming pools. Briefly stated, these advantages includethe following by way of example: the present device uses much lowervoltages below water, resulting in a very important safety factor. Iteliminates the requirements of relatively heavy and cumbersome gears andother mechanical contrivances for providing the turning motion. Itprovides a much more sensitive and sub tle program of response to itsenvironment which significantly decreases the chances of the devicebeing trapped in wall corners or near other specific configurations ofwall and increases the probability of the thorough cleaning of theentire surface within statistical limitations. It provides strongersuction and hence better cleaning abilities because of its use of anabovewater relatively high-voltage pump. It uses electronic logic andcontrol means which are lighter, more compact, reliable, inexpensive,and capable of better control than those heretofore known. It utilizescertain elements of pre-existing structure associated with swimmingpools, particularly, the pool skimming and filtration system pump. It issafer than previously known devices in other respects as well, as forexample by its elimination of most rotating machinery.

SUMMARY In its preferred illustrated form, this invention is a randommotion suction cleaner for swimming pool bottoms. It also has obviousextension of applicability to submerged surface in other types of tanks.Broadly, some aspects of the invention, particularly the control andlogic means are suitable for other applications, as has been described.

some of the advantages of the present invention over previously knownexpedients in this field have been set forth above in the discussion ofthe prior art.

It is an object of this invention to provide an electronic programmeddrive control to automatically direct a vehicle across a surface inresponse to sensing of obstacles.

It is an object of this invention to provide a suction cleaner forsubmerged surfaces in tanks.

It is another object of this invention to provide a suction cleaner forthe bottoms of swimming pools, adapted to move in a random pattern overthe bottom surface and to sense the walls of the pool or other obstaclesand to turn away from them.

The cleaner is provided with driving wheels directly operated bylow-voltage motors. The drive wheels on a given side are each capable offorward and reverse motion. The vehicle includes a suction inlet and aremovable strainer to catch large debris. The pumping means for thesuction is provided independently of the vehicle above the water leveland is connected to the vehicle by means of a hose. This permits the useof a more powerful suction pump with higher voltages without thenecessity of introducing these voltages into the water, and also permitsthe use of pre-existing swimming pool filtration and skimming pumpingand connection facilities. Means to float the hose or to reduce itsadverage density compared with that of the water are provided.

The vehicle has gathering means for the bottom de bris. It has right andleft sensing means to operate switches when contact is made with a wall.These sensing means are constructed so as to minimize the possibility ofanomalies or other instances of failure to respond. A completelyelectronic, completely solid-state, programmed logic and control meansis provided. This logic and control means responds to contacts of thesensors with the wall and controls the motors according to apre-selected logical program. Some important as pects of the control anddrive structure are that the driving wheels are not steered, but insteadtheir directions are fixed and all steering of the vehicle takes placeby selective forward, reverse, and pause states in the rotation of thedriving wheels; there is no gearing or other selective transmissionmeans depended upon to engage or disengage the wheels from the motormeans, and instead, the drive wheel or wheels on a given side of thevehicle are connected to a pair of motors, one of which is wired forforward motion and the other of which is wired for reverse motion; theduration of the various steps in the programmed cycle may beelectronically adjusted.

The vehicle may be provided with a decorative sheath so as to resemblean attractive or amusing creature, such as a turtle.

BRIEF DESCRIPTION OF THEE DRAWINGS FIG. 1 is a perspective view,partially and crosssection, of a swimming pool provided with thecleaning system.

FIG. 2 is a plan view of the vehicle, with the outside coveringpartially fragmented.

FIG. 3 is a cross-sectional view of the vehicle taken along line 33 ofFIG. 2.

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 showingthe connection between a sensing bar and a switch.

FIG. 4a is an enlarged detail elevation view, partially andcross-section of the override mechanism between the sensing bar and theswitch.

FIG. 5a is a block diagram of the sensing, logic, control, and drivemeans of the vehicle.

FIG. 5b is a schematic of the means of FIG. 50.

FIG. 6 is a detailed enlarged view, partially and crosssection,partially fragmented, of the upper termination of the hose.

FIG. 7 is a perspective view ofa magnetic connection between a sensorarm and a magnetic switch.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 best shows the overallsystem. Because the operative device includes a part that moves alongthe bottom surface, and in addition includes other parts, the entireoperative device is called the system and the part that moves across thebottom surface is called the vehicle. The vehicle is generallydesignated 10. It is shown in a typical position on the bottom surfaceof a pool generally designated II and having water 11a therein. A hose12 extends from the vehicle to the dry surface around the edge of thepool. The hose is connected to the vehicle with detachable connector12a. This connector, and others as may be desirable as matters ofdesign,may be made as swivel-type connectors to minimize twisting of the hoseor torque effects exerted by the hose on elements of the system.

The hose above water level is carried on a hose dispenser or reel 14 inoperating addition, the hose 12 is partially or completely unrolled fromthe dispenser 14, but in the stored condition, the hose is substantiallycompletely rolled up on it. The section of the hose 12b most remote fromthe vehicle 10, extends from the dispenser to a tee 15. This tee has onebranch leading to a hose section 126 which is connected to the pumpsuction. Another branch from the tee 15 is blocked with a water proofedgrommet 15a and permits the egress from the hose of the power line 71.The power line is provided with a connector 710 for connection to apower source.

The structure of the hose l2 and its contents, and of the tee 15 aremore fully explained below in connection with FIG. 6, and also, aspectsof the hose structure are further discussed in connection with FIG. 3.The power source itself is not shown. since the vehicle motors operateat 24 volts, the normal 1 10 volt AL. power supply is reduced in voltageby a transformer before connection to power line 71. The pump is notshown because it is intended that the pump already preexisting inconnection with a swimming pool shall be used for this suction purpose.Such pumps are routinely provided to run at normal power line voltages,such as l 10 volts (or higher voltages) and have capacities and pumpingheads already designed and provided to be suitable for the size andnature of the pool. These pumps are used in the filtration and skimmingsystems.

It is common for such pumps to have alternate inlets positioned atvarious points around the pool above the water surface where it isintended to connect ordinary pole-type bottom cleaners and hoses to suchinlets. Any one of these pre-existing available pump inlets may beconnected to hose section I20. It is a common expedient to have a hosesection 12b come off the inmost end ofa hose while on a reel. Forexample, the inmost end of the hose may be brought into the hub of thereel and out through one end thereof through a swivel connectron.

The general mechanical structure of vehicle I0 is best initiallydescribed in connection with FIGS. 2 and 3. The vehicle 10 is providedwith an outer covering or sheath 40, which is shaped to represent aturtle. It is provided with a head portion 400. The head portion 400 atleast is made flexible so that it will not interfere with the sensingactions of the device.

The vehicle chassis is generally designated 20. It includes a baseportion 21 on the base portion are provided vertically upstandingsupport panels or risers 21a. The outer covering, sheath or shell 40 ismounted for pivotable opening on the panels 210. A hinge pin 22 connectsa tab 41 on the cover with the panels 210 for the pivotable rotation. Alatch tab 47 is provided on the shell at the end opposite from thathaving the hinge tab 41. A latch mechanism, generally designated 30 isprovided. This includes a screw 32 which is hingedly connected to thelatch tab 47 by means of a pivot pin 33. A rear extension 57 from base21 is provided, and the latch locking means 34 bears against thisextension 57 to selectively hold the shell 40 in firm position on thechassis. The latch lock 34 is a threaded member fitting onto thethreaded latch screw 32.

A pair of scrapers 23 extend forwardly from the vehi cle. One of theseis mounted on each side of the vehicle and extends outwardly from thelongitudinal axis thereof, near the pool bottom surface. They arehelpful in scraping and loosening material to be removed from thecorners of the pool, which are often rounded, that is, provided with aradius or filet, in both the horizontal and vertical plane, and whichare difficult or impossible to directly reach with the suction opening.The scrapers are flexible.

A suction opening 24 is provided in the bottom of the vehicle throughthe base 21 in close proximity to the pool bottom surface. This suctionopening is an inlet to the chamber 49. A vertical partition, 25,circular in horizontal view, is provided on the base 21 to partiallyform the chamber 49. The circular partition 25 is provided at its upperedge with a resilient sealing member 25a.

A basket or strainer 26 is provided inside chamber 49 and resting onbase 21 over suction opening 24. The strainer 26 is provided with astrainer lid 27, which in turn is provided with a plurality of apertures27a to provide a straining function. This strainer 26 is removable fromthe vehicle when the shell 40 is unlatched and pivoted open. Thestrainer 26 is here shown in a simplified form for ease of illustration.It may be a mesh basket. It may be provided with apertures on all itssurfaces. It may, for example, be raised above the level of base 2] bymeans of lugs, and be provided with a mesh or with apertures on itsbottom surface as well as its side and top. It is apparent that theaddition of more straining area permits more efficient operation and alonger period of time between a required cleaning, and such variationsin the basket are a matter of obvious choice or design.

The internal structure of the shell 40 is such that it cooperates informing the chamber 49 and in retaining the strainer 26. A strainer lidhold-down tab 46 is provided extending inwardly from the shell 40. Thisbears on the lid of the strainer and helps hold it in position. Adownwardly extending tab, circular in horizontal view, 45, extendsinwardly from the shell and seats against the sealing member 25a to helpform the chamber 49. It is seen that chamber 49 is thus isolated fromthe surrounding water except through the inlet 24.

A head support block 28 is provided near the front end of the chassis toprovide an anchor for support to retain the decorative head 40a on thevehicle.

A control box 50 is provided above the rear wheel axles. This controlbox contains the electronic logic and control components of the vehicle.In FIG. 3, the printed circuit board assembly 69 is shown containedwithin the box 50.

Motors 51 are provided connected to the rear wheel axles. There areactually four such motors in function, although for each rear drivewheel the two motors associated with each such wheel share certainelements in common and are normally commercially obtained as a unit. Themotors are of the type known as gear-motors, and the output shaft runsat a substantially lower speed than the rotor. The output shaft of eachof these motors is directly connected to one or the other of the reardrive wheels. The nature of the motors 51 is explained more fully below.The control box 50 and the motor compartments are sealed water-tight toisolate the electronic components and motors from the environment, andthe motor compartments are filled with oil.

The vehicle is provided with a left traction belt 56L and a righttraction belt 56R. Each of these belts runs over a pair of front andrear wheels as shown in FIGS. 2 and 3. The front wheels are a left frontwheel SSL and a right front wheel 55R. The rear wheels are a left rearwheel 53L and a right rear wheel 53R.

The left front wheel is mounted for rotation on an idler shaft 54L andthe right front wheel is mounted for rotation on an idler shaft 54R. Theleft rear wheel is mounted for driven rotation on a drive shaft 52L andthe right rear wheel is mounted for driven rotation on a drive shaft52R. Each of these drive shafts is connected to a pair of motors 51. Itis understood that each shaft is connected to what appears to be asingle motor unit 51, and only one shaft extends from each motor unit.As has been explained, each motor unit contains within it functionalelements comprising a forward motor and a reverse motor.

The shell 40 is provided with an opening on the top which comprises anoutlet 48 from chamber 49. This outlet 48 is connected to the hose 12 bymeans of the connector 12a described in connection with FIG. 1. It isapparent that the interior of the hose is thus operatively connected tothe suction opening 24 through the strainer 26.

A power line 71 to supply power to the motors and to the logic andcontrol is carried inside the hose 12 in a manner described in moredetail below, and enters the body of the vehicle as shown in FIG. 3. Thepower line 71 is contained in a gas filled tube 72 in its passagethrough the hose l2, and together, the line 71 and tube 72 comprise aflotation-power assembly 70. Water proof connectors 73 are providedinside the body of the vehicle 10 and at these connectors, the gasfilled tube 72 terminates in a water proof seal, and the power linecontinues into the body to the elements requiring power. Where the powerline passes through the circular tab 45, it is provided with a waterproof grommet 74, to retain the isolation of chamber 49. The exact pathof the leading of the power line 71 to the electrical and electroniccomponents of the vehicle through the body of the vehicle is a matter ofdesign choice to permit opening of the top shell 40 for strainercleaning without unduly pulling or breaking any wires.

The general structure and general operation of the sensor arms can bebest understood in connection with FIG. 2 and to a lesser extent fromFIGS. 1 and 3. There is provided a left sensor arm generally designatedas 60L and a right sensor arm generally designated 60R. These armsextend outwardly and forwardly from the vehicle 10 at an angle,approximately 45 from the longitudinal axis of the vehicle. The broadconcept of such sensors of sensing arms has been known in the prior art,as indicated above. In general, the vehicle, once put in motion, movesin a straight line until one or the other of the sensors 60 touch anobstacle, usually the wall of the pool. Then, depending on which sensortouched first, the vehicle goes through a process to change itsdirection, and this broad cycle is continued in a selfcontrolled mannerso that the bottom of the pool is cleaned in a effectively random way.It is well known that from a statistical and empirical point of view,such random pattern covering of the surface is satisfactorily effectiveand efficient. The details of the turns are described in more detailbelow. Each sensor arm 60 is provided with a pin or shoulder bolt 61passing through a pin boss or shoulder 61a on the arm. The structure ofthe inboard part of the sensor arm 60 is shown in more detail in FIG. 4,and all that structure is described further below. The outboard orforward end of each arm 60 is provided with an outboard shoulder bolt orpin 66 passing through an outboard pin boss or shoulder bolt 670. On thepin 66 is provided a contact wheel 68. In most cases, it is the contactwheel 68 that makes first contact with an obstacle. Each wheel 68 isfree to rotate so as to minimize the possibility of a friction hangupagainst the obstacle. Such contact causes a slight horizontal rotationof the arm 60 around its inboard pivot pin or shoulder bolt 61.

If the vehicle 10 runs into an obstacle having an inwardly extendingangle or point, it will be appreciated that the contact could be madewith the point coming between the two extending sensors 60, and thevehicle could stop without either of the sensors being activated. Toobviate this problem, sensor arm extensions 670 are provided on eachsensor arm 60. These extensions 67a extend toward each other, toward themidline or longitudinal axis of the vehicle in the same horizontal planeas the arms 60. They are preferably bent as best shown in FIG. 2. Theyextend from a point between the ends of the arms 60 as shown. It hasbeen found that this location, which may preferably and conveniently beapproximately at the mid-point of the arm 60, provides a better geometryfor reliable sensing and activation of the switches than a location ofsuch extensions at the very forward ends of the arms 60. Bumpers 67b areprovided at the ends of each extension 67a. Preferably, these extensions67a curve or bend from an initial direction perpendicular to theextension of the arm 60 backwards to a direction more nearly approachinga line transverse to the direction of travel of the vehicle. The head40a, flexible as has been described, bends out of the way when contactis made in its vicinity. As shown in FIG. 3, the sensors are elevatedfrom and clear of the bottom of the pool.

The inboard structure of the sensor arms 60L and 60R and the means bywhich they activate the sensing switches are best shown in FIG. 4 andFIG. 4a. The front of the base 21 is shaped into upwardly extendingportions generally designated as a front support block 29, as shown inFIG. 2. This support block in general has the function of supporting thefront wheel assemblies and also is further differentiated into separateelements as best shown in FIG. 4. One support portion 29b forms part ofthe circular partition 25, and also serves as part of the overallsensing means. The other support portion 29a provides a support for thepivot of the arm 60. The shoulder bolt 61 rides in a bearing in supportportion 29a. Inboard of shoulder bolt 61, the arm 60 is extended to forma cam 64. An arm return spring 65 is provided to return the arm 60 toits neutral position after contact is removed. The spring 65 issupported between a spring pin 65a extending from the cam 64, and afixed position spring pin 65b extending from the support portion 291).

As shown in FIG. 4, the upper surface of cam 64 is an upwardly facingconcave surface. A cam follower or switch operator 63 extends downwardlyonto the face of cam 64. In the neutral position of the arm 60, thefollower 63 rests at the bottom of the concave upper sur face of thecam. The follower 63 actuates switch S2. The structure shown in FIG. 4for arm 60L is duplicated for arm 60R, which operates switch S1. Theswitch is mounted on a switch mount 62. The mount 62 is provided withdownwardly depending extensions 620 which form pivot stops or limits tolimit the maximum swing of the arm 60 from its neutral position. One ofthese pivot stops 62a is provided on each side of the cam 64 to limitits horizontal travel in either direction. One of the pivot stops 62a isshown in FIG. 4. In FIG. 2, it is understood that one of these pivotstops is provided on each side of the switch mount 62. It is apparcutthat when an arm 60 makes contact with an obstacle, the follower 63rises and actuates the switch S2, and that when the contact with theobstacle is broken, the follower 63 drops and the switch is no longerpressed.

A preferred form of a cam follower and its associated structure isillustrated in FIG. 4a. This form is adapted to operate a more commonlyavailable and economically obtainable type of switch S2 which permits alimited degree of travel and has a limited resilient bias to insurereliable return downwards of a cam follower. This preferred form of camfollower is generally designated 83. The switch mount 62 is providedwith a downwardly extending boss 62b. The follower, switch operator orplunger 83 is provided with laterally extending pins 85. A return spring84 is positioned around the follower 83 between the boss 82b and thepins 85. This spring 84 provides the main strong thrust for holding thefollower 83 against the cam 64 and insuring that it returns downwardlywhen the arm 60 returns to its neutral position after a contact.

Provision is made so that there is no damage to the switch or to anyother part of the structure by reason of the fact that the mechanicaltravel of the switch is smaller than the overall travel of the follower83 pivot for example, an hermetically sealed switch S2 of aneconomically desirable type may have a travel on the order of 0.050inches, whereas it is not easily practical to provide such a limitedscope of travel under the operating conditions in the remainder of thesensing structure. For this purpose, a lost motion or over travel meansis provided. This means comprises a secondary plunger 86 positioned foraxial movement within the recess 83a. The secondary plunger is biasedupwardly by an overtravel spring 87. The switch actuator 90 bearsagainst the top of the secondary plunger 86, and the compound plungerassembly moves vertically within the hole 620. It is apparent that asplunger 83 moves upward, the spring 87 is compressed and when its forceis great enough to overcome the resistence of the actuator 90, theswitch S2 is actuated. Thereafter. additional upward travel of plunger83 results in additional harmless compression of spring 87.

One advantage of the sensing arm-switch structure in this invention isthat the simple reliable switch is reliably actuated regardless of thedirection in which the arm pivots upon contact with an obstacle.

The structure of the tee 15, described above generally in connectionwith FIG. 1, is understood in more detail in connection with FIG. 6. Thehose section 12b contains a flotation-power assembly 70. This assemblycomprises a sealed, water tight, gas filled tube 72. The power line 71is contained within it.

The hose 12 containing power line 71, when full of water, would tend tosink and produce drag on the vehicle and some difficulty in handlingbecause of the 4 weight of the wire 71, even though the hose along wouldfloat. By providing the gas filled tube 72 inside the hose 12, a numberof functions are performed. One of these is that the hose-wire assemblythen tends to float. This insures that the hose is off the bottom andout of the way of the vehicle and also reduces other possibleinterference with the operation of the vehicle. It makes the hose 12more easily moveable, both by the vehicle and by an operator who maywish to shift it. Another function is that it provides a dry environmentfor the power line. Other functions are that it provides additionalinsulation for the power line and some additional protection againstchafing of the power line. The gas in the tube is normally simplyentrapped air. The relative dimensions of the hose, power line, and tubeare not critical. The hose may be of polyethylene and have an [.D. of 1/2 inches. The tube 72 may be of vinyl with an CD. of three-eighths inchand a wall thickness of approximately one thirty-second inch. Any air atall in the tube provides some benefit, and increased amounts of airprovide more of these benefits with the limitation that as the tube 72gets larger, the effective cross-sectional diameter of the hose 12 forthe passage of water and debris is reduced. Another limitation is thatthe size of the air tube should not be so great that there is aappreciable lifting effect tending to hold the vehicle off the bottom orto recude its traction. Less preferably tube 72 may be filled withnon-gaseous flexible material instead of air, as foamed insolated-cellflexible plastic, or the tube and air may be replaced by a sheath ofsuch material. The requirement is that the weight of the power line 71be offset by a surround having a density less than that of water.

At the dry or land end, at the tee 15, as shown in FIG. 6, the tube 72terminates in a sealed collar a around the power line 71. The power linepasses through one of the branches of the tee through a hole in thewater proof grommet a. The other branch of the tee leads to the hosesection 120 connected to the pump, as has been described. The tube 72may be terminated and sealed at the other end, within the body of thevehicle, in the same way.

The switches in the sensing means are normally off. They are preferablyof the moistureproof, non-snap type, with an integral push button oractuator. Preferably, they are of a low-bounce type, and may have anoperating force of approximately three pounds.

The motors in the prefered embodiment are 24 volts A.C. motors. Eachmotor may have a rating of 60 watts. Such motors are available forexample from the Molon Company. The motor unit includes one shaft. Thisshaft has on it two electrically isolated rotors, spaced along theshaft. There are two electrically isolated armatures, one associatedwith each of the rotors. The armatures are reverse wound. Thus, when onearmature is energized, the shaft rotates in a forward direction, andwhen the other armature is energized, the shaft reverses. Thus, thoughthis is a single housed unit, sharing certain elements, it is infunction two separate motors, operating in reverse directions. It is ofthe shaded pole type, and has an integral gear reducer so that theoutput at the shaft connected to the drive wheel of the vehicle may bebetween approximately 18 and 25 RPM. An advantage of providing this typeof reversing is that there is no necessity to provide capacitors whichwould be large at the low voltage used and which tend to discharge attwice the operating voltage. Thus, the under water electrical system ismaintained at a safe low voltage and the reliability of the equipment isincreased.

The overall logic and control is best broadly understood in connectionwith FIG. 5a. The two switches, which correspond with switch S1 and S2in the drawings, are connected through a switch interface 82 to a timerand logic section 93, which acts on a motor control section 94. Themotor control in turn operates the four functionally independent motorsall generally designated 51, and individually identified as left frontLF, right front RF, left rear LR, and right rear RR.

The pump to handle the suction will vary in its size and otherparameters depending on the pre-existing filtration and skimmingequipment at the pool, but its motor may be of the order of magnitude ofone horsepower and operates on full available line voltage.

FIG. 5b is a schematic drawing of the circuits involved to carry out thefunctions of the block diagram of FIG. 5a. The four functionallyindependent motors 51, individually identified LF, RF, LR, and RR asdescribed above, are found also in FIG. 5b. Elements S1 and S2 in FIG.5b correspond to switch 1 and switch 2 respectively in FIG. 5a.

Swtich l is part of the left sensing means and is operated by thesensing arm 60L. Switch 2 is part of the right sensing means and isoperated by the sensing arm 60R.

The program and logic of the electronic system and of the vehicle may bedescribed as a seven step program. Some important aspects orcharacteristics of the program are as follows. The vehicle turns in adirection away from the contacted sensor. Between each step involvingmovement there is a pause or halt. This pause or halt time preventsundue strain or damage to mechanical parts due to sudden reversals andalso prevents damage to or overheating of motors because of currentsurges due to sudden reversals. A very important aspect of the programis that after a contact is made, before a turning motion starts, thevehicle backs up in a straight line for a short distance. Then, the turnis made, and then the forward motion is resumed. The existence of theback-up step contributes in an important way to minimizing thepossibility of the vehicle being trapped against or between an obstacleor obstacles and going into a pattern of repeated coverage of a smallarea of the bottom in the vicinity of the obstacle or obstacles. Ifthere is no back-up, there is a higher possibility that the vehicle willnot be able to free itself from an obstacle to continue its randomcoverage of the bottom and that a rigid sensor arm may be broken duringa turn. If both sensors L and 60R are struck in succession before acomplete turn cycle has been effected, the system locks out the sensingmeans so that the second strike is ignored. If both sensors are strucksimultaneously, the vehicle will not be stalmated.

The seven step program or cycle when switch I is actuated is as setforth in the following table:

I. LF RF 2. Halt T 3. LR RR 4. Halt T 5. LF RR 6. Halt T 7. LF RF In thetable, the duration of time of the three successive half or pauseperiods are respectively identified as T, T and T LF means left forward,RF means right forward, LR means left reverse, and RR means rightreverse.

If switch 2 is actuated, the program as set forth above is the sameexcept that in step 5, the L and R are reversed. If one switch isactuated, the system sequences through its cycle with the other switchlocked out.

Steps 7 and l are the same, and represent the normal forward motion ofthe vehicle.

The above program for the sequence or cycling of a random motion devicewith contact sensors is in itself an improvement over previously knownmethods and mechines.

In FIG. 5b, in addition to the identification of elements given above,in general the coding of elements in the schematic is as follows: R,resistor; C, capacitor; 0, transistor, some of which are unijunctiontransistors (although Q12 Q15 are triacs); M, motor; D, diode; RL,relay; F.F., bistable multivibrator (flip-flop). The schematic has beendivided into sections by dashed lines, approximately divided intofunctional sections, including the blocks in FIG. 5a.

The power supply section is supplied with 24 volts A.C. from thetransformer as has been described. The 24 volts AC. is also supplieddirectly to the motors to operate them. Resistor R28, diode D32, R28 andcapacitor C8 comprise a half wave rectifier. Voltage to power the relaysis provided from the junction between R28 and D32. This is about 14-20volts DC. The voltage required for the logic circuit is 5 volts, andthis is provided by the remainder of the power supply, after R28 andD33. D33 is a zener diode which regulates the voltage.

In the motor control, for the four motors LF, RF, LR and RRrespectively, R21, R23, R25, and R27, and C4, C5, C6, and C7, are partof the motor starter circuits for the respective motors with which theyare associated in the schematic. Q12, Q13, Q14, and Q15 are triacs,which act as AC switches. They each operate on the motor with which theyare associated in the schematic. R20, R22, R24, and R26 are limitingresistors for the respective triacs with which they are associated.

The legend RL denotes a reed relay, and there is one of these relays foreach motor. In the schematic, one side of the relays are each denotedrespectively RLk, RL2, RL3 and RL4, and the other side of the relays areeach denoted respectively RLl RL2', RL3 and R134. A resistor R5] isprovided between the power supply and the relays.

In the bistable multivibrators or flip-flops, the outputs are identifiedas terminals and I, reset is R, set is S, and clock is C. These areconventional electronic circuit elements.

When power is applied to the vehicle 10, both FF] and F1 2 have theirterminals 0 high which prevents the diodes D1 and D2 from conducting.This state permits the pull-up resistor R1 acting through the isolationdiodes D3 and D4 to forward bias the relay driver transistors Q8 and Q9which turn on to ground, and which in turn energize relays RL1 and R12.These in turn turn on triacs Q12 and Q13, which start the motors LF andRF. This puts the vehicle 10 in its normal forward mode. This modecontinues indefinately if no switch S1 or $2 is actuated.

In that portion of the description immediately following, the functionsare described in terms of the left sense switch S1 being actuated, withthe corresponding effect when right switch S2 is actuated being insertedin parenthesis.

When the left sense switch S1 (or right sense switch S2) is closed,terminal 0 of FFI (or F1 2) goes low, causing diode D1 (or D2) toconduct. This stops the forward biasing of Q8 and Q9, thus openingrelays RL1 and RL2, which turn off triacs Q12 and Q13, causing themotors LF and RF to stop. At the same time, terminal 1 of FFl (or FFZ)goes high causing diodes D16 and D17 to conduct which through R4 anddiodes D14 and D15 forward bias Q10 and Q11. The relays RL3 and RL4close and Q14 and Q15 turn on starting the motors LR and RR.

At the same time, when the switch S1 closes, the low state of terminal 0of FFl (or FFZ, in the case of closing of switch S2) shuts off theforward bias, which is supplied by R5, of master timer gate Q1 and resettransistor Q2. The lock-out of timer multivibrator FPS and timingcapacitor C1 ceases and C1 begins charging through timing resistor R7,R9 and D18. When the voltage across Cl rises to a critical point, theunijunction transistor Q3 fires, causing pulse generator Q4 to create anegative pulse which changes the state of FF3. Terminal 0 of FF3 goeslow, causing D13 to conduct, turning off Q10 and Q11. Relays RL3 and RL4then open, causing triacs Q14 and Q15 to turn off, which cause motors LRand RR to stop. Terminal 1 of F1 3 goes high, and D5 (or D9 if S2 isclosed) and D6 (or D) cease conducting, forward biasing the transistorsQ8 and Q11 (Q9 and Q10) through R2 (or R3). Relays RL1 and RL4 (or RL2and RL3) close and triacs Q12 and Q (or Q13 and Q14) turn on, startingmotors LR and RR (or motors RF and LR). The unijunction transistor Q3again fires, changing the state of F1 3 after a time period determinedby C1 and R8 and R9. Terminal l of FF3 goes low, causing D6 and D10 toconduct,

turning off Q8 and Q11 (or Q9 and Q10). This causes all motors operatingon the alternate mode to stop. At the same time, pulse generator Q5resets all the multivibrators to their original states, and the motorsLF and RF again run. The pause or half interval timer permits the motorsto come to a complete halt before reversal. This timer operates at thestart of each change of state. When either sense switch S1 or $2 isclosed, FF4 changes state permitting timing capacitor C3 to startcharging, and, as in the other time, when the critical point is reached,causing the unijunction O6 to fire and reset FF4. At the start of thetiming cycle, terminal 0 goes high and releases the clamp diode D20permitting charging of timing capacitor C3. The terminal 1 is low,causing forward bias to be removed (for the timing period) from Q8, Q9,Q10, and Q11, thus turning off all relays and triacs, and thus turningoff all motors. The initial starting pulse comes from the senseswitches, when closed, through the decoupling diodes D21 and D11.Remaining pulses come from the master timer through decoupling diodeD23.

Certain aspects of the operation of the circuit shown in schematic FIG.5b can be further described in additional detail. When switch S1 isactuated and closed, a negative pulse sets FF! terminal 0 low andterminal 1 high. The pulse also goes through D22 to the reset R of FF4.When FF4 resets, terminal 1 of FF4 goes low and shuts off alltransistors Q8, Q9, Q10, and Q11 in the motor control. Then diodes D24,D25, D26 and D27 conduct and therefore all the transistors Q8-Q11 areturned off and clamped. Therefore, all the motors stop.

When FFl terminal 0 goes low, it resets FF2 at reset R. Therefore,switch S2 cannot set FF2 at set S, because it is clamped or locked out.

Note that most of the description relates to the function following anactuation of switch S1. When switch S2 is actuated instead, there is anobvious symetrical reversal in the function as is clear from theschematic.

Before an initial switch contact, Q1 and Q2 are both conducting. Q1keeps C1 from charging and Q2 keeps FF3 in reset. This inhibits thetiming circuit and prevents it from interfering with the forwardoperation of the vehicle.

After S1 is closed, neither Q1, Q2, Q8 or Q9 conduct since D1 and D2conduct and both sides are low. As explained, after closing of S1, FF4is reset and thus all the motors are stopped.

The timer is now discussed. As Q2 turns off when S1 is closed, itreleases reset R on FF3 so that terminal 0 goes high.

When 01 turns off, it releases Cl so that the capacitor C1 can nowcharge. This charging times the first halt or pause step. It changesthrough D18, R7 and R9 because terminal 1 of FF3 is now high.

When the C1 voltage reaches the critical level for that capacitor, theunijunction Q3 fires (conducts). When Q3 conducts, Q4 also conducts. Thepulse to trigger Q4 is developed from O3. When Q4 conducts, the clockinput C of FF3 goes low, so that FF3 flops or changes state.

When switch S1 is closed, flip-flops FFl and FF4 reset, and capacitor C1and C3 both start charge. C3 charges fully before C1, so the unijunctionQ6 fires first. It turns on Q7, and permits the capacitor to discharge.The pulse from O7 clocks FF4 at clock terminal C. Since 07 conducts, theclock C terminal goes low. Before this pulse, terminal 0 of FF4 was highand terminal 1 was low. So, after the pulse, the FF4 terminal goes lowand the flip-flop FF4 clocks to the set state. C3 cannot rechargebecause FF4 tenninal 0 has gone low. Terminal 1 of FF4 has now gonehigh, so that all the control transistors are unclamped. Therefore, twoof the motors are now free to run. These are the reverse motors RF andRR.

The reverse motors are actuated as soon as switch S1 is closed, butbecause of the FF4 clamp, the actuation of the path is of no effect.When C3 charges, FF4 changes state, the control transistors areunclamped, and the reverse mode is in operation.

Electrical reverse motor path is Q10, R18, D14, R4 (and through D16, ifS1 is closed). If S2 is closed, the path is through D17 instead of D16,and the path is through Q11, R19, D15, and R44, and is otherwise thesame.

So, the charging time of capacitor of C3 determines the length of thefirst stop, pause, or halt. Resistor R13 sets the length of this halttime by adjusting the charging time of C3. C3 is shorted through D20 tothe low terminal 0 of FF4, so C3 does not recharge.

Then, capacitor C1 starts charging, and when fully charged, it changesthe state of FF3, through 03 and Q4, and also resets FF4 through D23.When C1 is charged, FF3 sets terminal 0 low and terminal 1 high. FF4 isreset with terminal 0 high and terminal 1 low. When FF4 terminal 1 goeslow, it clamps the control transistors. When FF4 terminal 0 goes high,C3 can start to charge again. C1 starts to recharge through D19 and R8.This provides the halt or pause after the vehicle reverse step in thecycle.

The next step is the turn mode. FF3 terminal 0 low and terminal 1 highset permits the setting of PH to have the turn mode go on. Through D1,09 turns on through D1 l. 010 turns on through D12, so, in the turnmode, relay RL2, operating through control transistor Q9, permits motorRF to operate, and relay RL3, operating through control transistor Q10,permits motor LR to operate. During the turn mode, C1 is charging and C3has discharged. Then, Cl fully charges, setting the time period for theturn mode, and clocks FF4 to the reset state, and FF3 to set terminal 0low. When FF4 is reset, C3 restarts to charge. When FF3 terminal 0 islow, Q pulses and resets PH and FFZ. The system is now back to itsinitial state with the forward motors in operation.

It is understood that the diodes D3-D8, and D11-l5 are isolation diodes.And that diodes D28-D31 form a similar function in connection with therelays. It is noted that resistors R7, R8, and R13 are shown as variableresistors in the schematic. They are shown this way because setting ofthese resistors determines the various timing rates, but in ordinarycommercial forms of the invention, once these resistance values arechosen to select pre-determined desirable time periods, it is notnecessary to provide them in the unit as variable resistors. It isunderstood that an operable circuit is disclosed in the schematic itselfand the foregoing description helps to explain the operation of thiscircuit, and that since most of the description relates to thecircumstances under which switch S1 is closed, certain obvious otherpaths and elements having the same logic but controlling differentmotors are involved if switch S2 is closed first.

In general, the element generally designated in FIG. 1 is called thevehicle, and the vehicle in addition to the other elements, includingfor example the hose, pump, etc, is called the system. The motors,wheels, and traction belts are called the drive means. The arms andtheir associated structure including the switches are called the sensingmeans. The elements shown in FIG. 5b, excluding the motors and switches,are called the logic and control means.

The invention as described is of the preferred embodiment and theelements of the invention combine to produce advantageous results.However, it is possible within the scope of this invention to modifycertain elements of the combination and still retain inventiveadvantages. For example, the pump could be provided on the vehicleitself, with the sacrifice of certain advantages, as has been explained.It would be possible in stead of using four functionally independentmotors, to use two motors and make them reversible motors, with thedisadvantages that have been previously explained. It is possible,instead of using the rubber traction belts 56, to couple the frontwheels to the drive wheels with chains or gears, although such astructure is not preferred and does not have the full advantages of thepresent structure. It would be possible to provide the vehicle withthree wheels instead of four, substituting a single wheel for the twofront wheels, although this would not be preferable. It would bepossible to provide a motor on each of the four wheels, with one reverseand one forward on each side.

It would be possible to use an electric brake or clutch on the motorsinstead of a halt or pause. This would be a more expensive expedient,but would speed up the cycle. It would be possible to provide sensingarms longer than those presently illustrated and to make them flexible.In such a structure, the cycle could lead to an immediate turn ratherthan a back-up step, with the compliance of the flexible arm permittingthe immediate turn without breaking the arm or forcing the vehicle toslip and the extra length of the arm reducing the changes of the vehiclebeing stalmated. Such a structure is not considered preferable.

It is possible and desirable to provide a switch to pre vent operationof the vehicle drive motors out of water, to avoid overheating of themotors or the triacs. This means may be a bouyancy switch, such as aping-pong ball floating in a retaining cage, or a pressure-actuator orsuction-actuated switch.

The logic can be performed by means of relays or by a combination ofrelays and rotary switches. The timing may be performed by motor drivenadjustable cams or by feeding screws, or by thermal relays. It isunderstood that such non-electronic, means which in some cases includeadditional motors, mechanically moving parts, and parts subject tounreliability under the desired service, are not considered preferable.Fluidic logic, using an hydraulic system could be used for the logic. Itcould use the pump suction for power and utilize valves instead ofswitches as part of the sensing means. Fluid motors driven by the pumpmight be used for the primary drive of the vehicle. It is understoodthat such a structure is not fully disclosed herein, but for the purposeof certain aspects of the invention, particularly the programming, andthe concept of the separate pump and, the hose system, for example, suchfluidic logic is considered an equivalent.

Referring to FIG. 4, instead of a cam system, all mechanical contactcould be avoided, by using a magnet and a reed switch, or by using photocells. FIG. 7 shows a type of connection between a sensor arm 60L and aswitch, in which the coaction is magnetic. The arm, generally designated60L is provided with a boss fila' and pivots around a pin 61. A verticalextension 100 of the arm is provided near one end thereof. Thisextension carries a permanent magnet 101 which is exposed at or near theend vertical surface of the extension 100.

A magnetic reed switch 103 is provided in the sup port portion 290',with its magnetically sensitive surface facing toward the magnet ll. Thearm is spring biassed to a neutral position in the same manner as setforth in connection with the embodiment of FIG. 4. When the arm is inits neutral position, the magnet is centered over the switch and theswitch remains open. When the arm pivots, and the magnet therefore movesfrom a central position with respect to the switch, in either direction,the switch closes. The switch remains closed until the magnet returns toa central position, and the logic circuit responds to this signal in thesame manner as has been described above.

The sensitivity of this switch is a function of the gap between themagnet and the switch, the strength of the magnet, and the sensitivitycharacteristics of the switch, and the choice of a desirable sensitivityas a matter of obvious design. For example, the magnets are commerciallyavailable in one-fourth inch diameter, and have lengths for example of linch, inch, inch, with the longer the length, the greater the flux. Ithas been found that magnets of this diameter with lengths of "/8 inch orinch, gapped approximately /8 inch from a magnetic reed switch, aresatisfactory. Suitable reed switches comprise a glass tube containingtwo arms which are magnetically moveable. Such switches are availablefor example from Hathaway Industries, lnc., General Reed, and GP. ClareCo.

This type of switch actuation is advantageous in that it eliminatesmechanical connection to operate the switch and thus reduces thepossibility of failure of the system because of corrosion or fouling bydebris. This type of switch actuation is in some senses a preferableembodiment.

The strainer, as shown in FIG. 3, can be made disposable, instead ofcleanable. it may be provided outside the vehicle. If the pump is to bemounted on the vehicle, a filter can be included. It is noted that inthe preferred embodiment illustrated, the vehicle includes a strainer,not a filter, since any filtration takes place in connection with thepre-existing pump which is part of the pool facility.

The reel, as shown in FIG. 1, can be made a portable unit, withcompartments or other provision to carry the vehicle, and can carry atransformer and main switch. The size of the strainer can be expanded tocope with conditions involving many leaves for example. One possibilityis the provision of a over size strainer system on the back of the unitinstead of the strainer contained within the interior of the vehicle.

electrical connector swivels may be used where required, just as thehose swivels, as is obvious.

A transverse brush, stationary with respect to the vehicle, may bemounted on the vehicle just to the rear of the inlet 24, to loosendebris and kept it swept into the hose served by the suction.

The system can be used for cleaning industrial tanks as well as swimmingpools.

It may sometimes be desirable to operate the vehicle by direct remotecontrol, rather than to permit it to move randomly, For example, suchcontrolled operation may be useful in certain areas of larger tanks.This control may be by wire or even by radio or other wireless means.Such remote control operates the switches S1 and S2. Since such controlwould typically be exerted only part of the time on the random motionvehicle otherwise as claimed and described, it is understood that theclaims include the concept.

It is understood that the foregoing mentioned modifications are notintended to be exclusive or to limit the scope of the claims, but areintended to suggest certain modification from the preferred embodiment.It is not maintained that each of these modifications would necessarilyresult in an equivalent structure to that of the preferred embodiment.

I claim:

1. A random motion vehicle having a forward end and normally adapted tomove in a straight line with said forward end leading across ahorizontal surface, to sense an obstacle, to turn away from saidobstacle, and to continue to move in a changed direction with saidforward end leading, said vehicle comprising,

a base, said base supporting the following means,

only a left side forward end obstacle contact sensing means and a rightside forward end obstacle contact sensing means,

a left side independent drive means and a right side independent means,each said drive means including at least one motor and at least onewheel, each said wheel being rotatable only in a plane parallel to thedirection of motion of said vehicle and driving a horizontalsurface-contacting traction belt,

a logic and control means operatively connected to said drive means andsaid sensing means to turn said vehicle to change said direction ofmotion, by sensing an obstacle contact sensing signal from one of saidsensing means causing said logic and control means to initiate aprogrammed cycle of instruction signals to said drive means, said cyclebeing; left and right drive means pause, left and right drive meansreverse; left and right drive means pause; one of said drive means drivereverse and the other of said drive means drive forward, left and rightdrive means pause; left and right drive means resume normal forwarddrive.

2. A method of controlling a random motion vehicle having a first andsecond side, and a front and back, so that normal operation is in astraight line with said front leading and so that obstacles are turnedfrom without a repeated pattern, a sensing means on each of said sides,and independent drive means on each of said sides, each of said drivemeans being capable of for ward or reverse motion, comprising the stepsof normally operating both drive means forward to provide straight linevehicle motion in a first direction, and when an obstacle is contactedby said sensing means on said first side, automatically turning saidvehicle from said obstacle by operating both said drive means in reversemotion, then operating said drive means on said first side in forwardmotion and said drive means on said second side in reverse motion untilsaid turn is completed, and then resuming normal straight line forwardmotion of said vehicle in a second direction by operating both saiddrive means forward.

3. A method as set forth in claim 2 wherein after said contact is madeby said sensing means on said first side, said sensing means on saidsecond side is inoperative until all steps have been completed.

4. A method as set forth in claim 2 wherein between each of the recitedsteps, there is provided a period of pause during which both drive meansare inoperative. k

1. A random motion vehicle having a forward end and normally adapted tomove in a straight line with said forward end leading across ahorizontal surface, to sense an obstacle, to turn away from saidobstacle, and to continue to move in a changed direction with saidforward end leading, said vehicle comprising, a base, said basesupporting the following means, only a left side forward end obstaclecontact sensing means and a right side forward end obstacle contactsensing means, a left side independent drive means and a right sideindependent means, each said drive means including at least one motorand at least one wheel, each said wheel being rotatable only in a planeparallel to the direction of motion of said vehicle and driving ahorizontal surface-contacting traction belt, a logic and control meansoperatively connected to said drive means and said sensing means to turnsaid vehicle to change said direction of motion, by sensing an obstaclecontact sensing signal from one of said sensing means causing said logicand control means to initiate a programmed cycle of inStruction signalsto said drive means, said cycle being; left and right drive means pause,left and right drive means reverse; left and right drive means pause;one of said drive means drive reverse and the other of said drive meansdrive forward, left and right drive means pause; left and right drivemeans resume normal forward drive.
 2. A method of controlling a randommotion vehicle having a first and second side, and a front and back, sothat normal operation is in a straight line with said front leading andso that obstacles are turned from without a repeated pattern, a sensingmeans on each of said sides, and independent drive means on each of saidsides, each of said drive means being capable of forward or reversemotion, comprising the steps of normally operating both drive meansforward to provide straight line vehicle motion in a first direction,and when an obstacle is contacted by said sensing means on said firstside, automatically turning said vehicle from said obstacle by operatingboth said drive means in reverse motion, then operating said drive meanson said first side in forward motion and said drive means on said secondside in reverse motion until said turn is completed, and then resumingnormal straight line forward motion of said vehicle in a seconddirection by operating both said drive means forward.
 3. A method as setforth in claim 2 wherein after said contact is made by said sensingmeans on said first side, said sensing means on said second side isinoperative until all steps have been completed.
 4. A method as setforth in claim 2 wherein between each of the recited steps, there isprovided a period of pause during which both drive means areinoperative.